Various processes have been used in the past in forming socket wrenches, extension bars, adapters and the like. These devices such as the socket wrench itself are standard devices, well known in the art. A conventional square drive socket is provided at one end of the socket wrench and is releasably attachable to a drive tang of a handle unit for a ratchet, for example. A fastener socket is coaxially formed at an opposite end of the wrench. The fastener socket is commonly serrated or of hexagonal cross-section. A through-hole may extend between the coaxially aligned sockets. The through-hole serves to provide clearance, for example, for a shank of a bolt on which a hex nut is threadably engaged with the nut received within the hex fastener socket. For a quality product, such socket wrenches are formed of alloy steel. Standard screw machines conventionally have been used in the manufacture of such wrenches which normally require several sequential machining operations.
Drive socket openings for such wrenches commonly have a recess for receiving a spring-operated ball, for example, in a tang of a drive handle for retaining the socket wrench and handle attachment in driving engagement. However, problems are frequently encountered in forming such recesses in socket wrenches and the like because of long standing difficulties in achieving consistency and accuracy in the size, shape and location of a recess in a face of the drive socket opening while also insuring that the depth of the recess is consistently accurate, particularly when each face of the drive opening has a recess. Specifications for female ends of such square drives for hand, power and impact wrenches are set forth in Table 7, The American Society of Mechanical Engineers publication ASME B107.4M-1995.
When such parts are being produced by machining operations such as turning or index milling operations, for example, how one sets a cutter and how one sets the travel of the cutter are variable but important functions. If the drive opening is not precisely dead center relative to a major longitudinal axis of the workpiece or if the cutting tool itself is somewhat off center, any resulting product will be nonconforming because the recesses are of different depth, or the recesses are misaligned from a symmetrical centered position in the faces of their respective drive opening, or the recesses are not axially aligned relative to the major longitudinal axis of the part. Moreover, such machining processes require specialized equipment, are expensive if not fully automated, suffer from limited tool life and resultant defects such as burrs.